A conventionally known push switch has a configuration in which the upper side of a case accommodating a switch contact portion is covered with a protective sheet (for example, refer to Patent Literature (PTL) 1).
The push switch disclosed in PTL 1 includes a case formed in a box shape having an opening in the upper surface. A movable member (movable contact) formed in an upwardly convex dome shape is disposed in a concave portion surrounded by a wall part of the case. The protective sheet is disposed on the case so as to cover the concave portion. The edge portion of the protective sheet mounted on the upper end of the wall part of the case is fixed to the case by welding through laser irradiation.
During operation of this push switch, a downward force is applied to the protective sheet and transmitted to the movable member, causing the movable member to be deformed (elastically reversed) into a downwardly convex shape. With this, the lower surface of the movable member is brought into contact with a center contact formed on the inner bottom surface of the concave portion of the case, and thus the push switch turns ON. When the force is no longer applied to the protective sheet, the movable member is deformed (elastically returns) into the original shape (upwardly convex dome shape), and thus the push switch turns OFF.